Session (Start/Register/Deregister/Compact)

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already indicate destructiveHint=true, meaning the tool modifies state. The description adds no behavioral context beyond 'lifecycle', failing to explain what gets destroyed, what side effects occur (e.g., during compaction), or any prerequisites like authentication or rate limits.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is very short (two sentences) and front-loaded with 'USE WHEN', making it easy to scan. However, the extreme brevity sacrifices completeness, and the examples are helpful but insufficient to cover the tool's complexity.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given 14 parameters, no output schema, and destructive behavior, the description provides almost no context. It omits parameter descriptions, return values, and behavioral details, making it inadequate for an AI agent to use correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0% and the description only mentions 'goal' and 'summary' in examples, ignoring 12 other parameters like 'blockers', 'decisions_made', and 'create_checkpoint'. The description fails to explain the meaning or usage of these parameters, leaving the agent with no guidance.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states 'Session lifecycle' and provides examples with operations like 'start' and 'compact', giving a clear idea that the tool manages session states. However, it lacks specificity about what exactly 'orientation, registry, compaction' entail and does not differentiate from siblings like 'plan' or 'think', which also manage state.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description only says 'USE WHEN: Session lifecycle' and shows two example calls. It does not specify when to avoid this tool, nor does it provide alternatives or criteria for choosing between session and sibling tools such as 'autofix' or 'plan'.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.